Clinical Tropical medicine

Question 1

Stool Microscopy findings:
Shigella

No: can be difficult to distinguish clinically between bacillary and amoebic dysentery

Answer 1

Leukocytes (pus cells)

Question 2

Stool microscopy findings:

Amoebic dysentery

Entamoeba histolytica

Answer 2

Haematophagus trophozoites

Confirmation is made by stool culture, serological and biochemical tests

Question 3

Infective causes of acute diarrhoea with blood

Answer 3

Bacillary dysentery (shigellosis)
Amoebic dysentery Enterohaemorrhagic EColi
Campylobacter enterocolitis
Salmonella enterocolitis
Clostridium Difficile (associated with paeudomembranous colitis)
Balantidium coli enterocolitis
Massive trichinosis infection
S.mansoni, or S. japonicum 
CMV in immunocompromised
Yer Sonia enterocolitis

All may cause diarrhoea without blood.

Non infectious causes include IBD, colorectal cancer or polyps, ischaemic colitis.

Question 4

Enterohaemorrhagic EColi

= EHEC

E.g. EColi 0157

However there are many other serogroups

What is the toxin responsible?
How is it treated?

Answer 4

Faecal testing for Shiga toxin should be performed,

Along with cultures for EColi 0157;H7.

The presence of an outbreak and exposure risk is often found in the history

Inflammatory, haemorrhaging colitis and HUS

Antibiotics are not indicated as they are associated with increased duration and increased risk of HUS.
Avoid antimotility drugs.
Oral rehydration and supportive care

Question 5

What is HUS?

Answer 5

Haemolytic Uraemic syndrome

Microangiopathic haemolytic anaemia, thrombocytopenia, renal failure and cns involvement. Clinical features overlap with those of TTP in which CNS involvement is much more common.